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Full-Text Articles in Mechanical Engineering

Numerical Modeling Of Advanced Propulsion Systems, Peetak P. Mitra Oct 2021

Numerical Modeling Of Advanced Propulsion Systems, Peetak P. Mitra

Doctoral Dissertations

Numerical modeling of advanced propulsion systems such as the Internal Combustion Engine (ICE) is of great interest to the community due to the magnitude of compute/algorithmic challenges. Fuel spray atomization, which determines the rate of fuel-air mixing, is a critical limiting process for the phenomena of combustion within ICEs. Fuel spray atomization has proven to be a formidable challenge for the state-of-the-art numerical models due to its highly transient, multi-scale, and multi-phase nature. Current models for primary atomization employ a high degree of empiricism in the form of model constants. This level of empiricism often reduces the art of predictive …


Thermoelectric Transport In Disordered Organic And Inorganic Semiconductors, Meenakshi Upadhyaya Jul 2021

Thermoelectric Transport In Disordered Organic And Inorganic Semiconductors, Meenakshi Upadhyaya

Doctoral Dissertations

The need for alternative energy sources has led to extensive research on optimizing the conversion efficiency of thermoelectric (TE) materials. TE efficiency is governed by figure-of-merit (ZT) and it has been an enormously challenging task to increase ZT > 1 despite decades of research due to the interdependence of material properties. Most doped inorganic semiconductors have a high electrical conductivity and moderate Seebeck coefficient, but ZT is still limited by their high lattice thermal conductivity. One approach to address this problem is to decrease thermal conductivity by means of alloying and nanostructuring, another is to consider materials with an inherently low …


Electro-Thermal Transport In Two-Dimensional Materials And Their Heterostructures, Arnab K. Majee Jun 2021

Electro-Thermal Transport In Two-Dimensional Materials And Their Heterostructures, Arnab K. Majee

Doctoral Dissertations

”Smaller is better” is the mantra that has driven semiconductor industry for the past 50 years. The on-going quest for faster electronic switching, higher transistor density, and better device performance, has been driven by a self-fulfilling prophecy popularly known as Moore’s law, according to which the number of transistors per unit area of a chip doubles itself approximately every two years. A modern smartphone has about 8 billion transistors, which is as large as current earth’s population. Although each transistor dissipates negligible power, but the collective power dissipation from all the transistors in an electronic gadget and inefficient heat removing …


Characterization Of Near Isothermal Compression And Expansion For Energy Storage, Saiid Kassaee May 2021

Characterization Of Near Isothermal Compression And Expansion For Energy Storage, Saiid Kassaee

Doctoral Dissertations

As the global share of electricity generation from intermittent renewable energy sources increases, developing efficient and scalable electricity storage technologies becomes critical to modernizing the grid, matching the supply and demand, and raising the capacity factor of renewable generation. The Ground-Level Integrated Diverse Energy Storage (GLIDES) is an efficient energy storage technology invented at Oak Ridge National Laboratory (ORNL). GLIDES stores energy by compressing gas using a liquid piston in pressure vessels benefiting from employing hydraulic turbomachinery which are more efficient than gas turbomachinery. Therefore, GLIDES has higher round-trip efficiency (RTE) than Compressed Air Energy Storage (CAES). Since GLIDES employs …